Cellulose composition



. substance, I

Patented May 31, 1927.-

UNITED sT' 'TEs 1,630,752 PATENT OFFICE.

WILLIAM G. LINDSAY, or" N WARK, new JERSEY, ASSIGNOR Td "ran CELLULOIDoomrnmr,

A CORPORATION OF NEW JERSEY..

I cELLuLosn courosrrron.

No Drawing.

' This invention relates to. a process for rendering certain inflammablematerials, or compounds, non-inflammable, and to the preparation ofcommercially use ful non-inflammable articles, such as paper textilefabrics, cellulose plastics, pyroxylin plastics and'the like. 4

The degree of non-inflammability sought for is that which will notpermit of a self sustaining combustion, after the application of a flameat ordinary or normal tempera ture. This degree of non-inflammabilitywill however, be varied according to desired conditlons.

I have discovered that inflammable materials which permit of a selfsustaining combustion by the application of a flame at ordinary' ornormal temperature may-be prevented from burning under ordinaryconditions and rendered non-inflammable provided there is present insuitable combination V a heat absorbing compound capable of abthe majorpart sorbing or taking up through decomposition, volatilization, orother change, all or of the heat that would be necessary to raise thematerial or its com- 1 ponents to the point at which ignition could besustained.

This heat absorbing, or .endothermic, substance or compound. should beof such I nature that it will decompose, or OthGIWlS.

be in condition to absorb-heat,before or when the temperature ofcombustion of the. ma-

terial to be rendered non-inflammable has been reached. The absorptionof heat will thus proceed at such a rate asto prevent the combustiblematefial from attaining its temparature of ignition. The endothermicsubstance or compound will also be selected having in view othercharacteristlcsbesides its heat absorbing capacity that it may bedesired to impart other properties to the resultant product. Therelative proportions of the combustible substance, i. e., the substanceto be rendered noninflammable, and endothermic or heat absorbingsubstance, will be varied somewhat to meet conditions of stren th,plasticity, transparency, or other desira le characteristics, but ingeneral will be dependent upon the amount of decomposition, in heat unitequivalents, that can take place at or below the temperature at whichcombustion could be sustained by the exothermic compound if the heat ofcombustion were not absorbed at on decomposition in Application neeApr-i125, 1922. Serial No. 556,533.

a greater rate than that at which it could be liberated. The generalrule is that a suflicient quantity of endothermic substance should beemployed to absorb upon its decomposition a suiiicient amount of heat toprevent a sustained combustion of the said exothermic substance. v

In carrying out my invention, any one of a number ofproducts may be theaim. The characteristics of these products may vary from that of a hard,nonmoldable, dense solid sheet material which may be used for cuttingout various objects such as brush backs, mirror backs, knife handles,etc., to that of a. thin, highly flexible product which may be usedpaper and the like or which can be used in place of various-textiles andother flexible materials. The flexible compound may also be used as asubstitute for leather. It may also possess the necessarycharacteristics required in compounds that are to be molded such Imolded brushes, mirrors, etc.

In carrying out the invention the procedure will vary according to thenature and physical properties of the material treated.

The exothermic substance which I propose to use will benitrocellulose,'acetylcellulose, or some cellulosic ester, ether,derivative, or compound.

In the, following examples I give such proportions as will .beapplicableto compounds containing nitrocellulose, as this 'is the most inflammableof the cellulose derivatives and any substance that may be in corporatedwith the nitrate for the purpose combus-- of'reducing, limiting orpreventing tion will be efiective with other compounds of cellulose, andas a matter of fact, with cellulose itself. U

The permanent or nonvolatile solvents generally referred to asthelasticizing agents and which are to be com ined with the pyroxylin orother cellulose derivative for the purpose of bringing about thenecessary conversion, etc. in the course of manufacture, should be ofsuch nature that the point of ignition is relatively high. .In myexperiments I have found t at the organic phosphates possess thenecessary. characteristics of solubility and at the same time possessthe requisite temperature of ignition.

I The most satisfactory results are produced with the aromaticphosphates because oi as molded 7 boxes, molded handles,

for the veneering of fabrics,

their relatively high stability and resistance to decomposition, andbecause they possessatthe same time the necessary solvent orplasticizing efl'ect on the nitrocellulose, as well as a relatively highignition point.

To a mixture of -nitrocellu-lose and an aromatic phosphate, as forexample, liquid tricresylphosphatc, I add a suflicient amount ofhexachlorethane to prevent the combined mixture from sustaining ignitionupon the application and withdrawal of a flame. An example ofproportions for this purpose is 100 parts of pyroxylin, 75 parts ofliquid tricl'csyl )hosphate, and 125 parts of hexachlorethane (C 01Material of this composition, when numufacturcd according to the usualmethods as obtain in the proxylinplaslic industry, will possesshardness, toughness and moldability in similar degree to the usualvarieties of celluloid, manufactured in the form of ivory, opaque colorsand the like.

In the manufacture of these non-inflam mable compounds I proceedsubstantially as in the manufacture of ordinary pyroxylin plasticmaterials incorporating the hexachlorethane compound with the soaked orcolloid izcd mass of pyroxylin and liquid tricresylpl'losphate prior tofinal mastication on the rolls. This incorporation may be effected inkncaders or the hcxachlorethane compound may be directly added duringthe course of mastication on the rolls. The hexaehlorethane compound mayalso be incorporated with the pyroxylin in the same operation in whichthe liquid tricresylphosphate is incorporated, the method for which isdescribed in my U. S. Patent No 1,233,- 374, granted July 17 1917. I

In the choice of liquid volatile solvent, I may select any one or acombination of a number of the common ordinary solvents, such asmethylalcohol, ethyl alcohol, acetic ether, acetone, amyl acetate, orthe various commercial grades and mixtures of these compounds as areordinarily found upon the market.

In the manufacture of the flexible non-inflammable compound having theproperties of leather and the like, I proceed as in the examplespecified but instead of employing 75 parts of liquidtricresylphosphate, I increase the amount to 200 parts pyroxylin.Material of this composition may be worked up according to the usualmethod for the manufacture of pyroxylin plastic compounds and producedin the form of sheets by shaving from a block, or it may be dissolved ina suitable proportion of solvent such as WOOd alcohol, acetone and thelike and spread upon a suitable surface such a textile fabric, leatherand the like.

I claim Y 1. A composition containing a cellulose ester and an aromaticphosphate and in close association therewith hexachlorethane.

2. A composition containin a cellulose ester and tricresylphosphate inadmixture with hexachlorethane.

3. A composition containing pyroxylin,

an aromatic phosphate, and hexachlorethane.

4. A composition containing pyroxylin, tricresylphosphate andhexachlorethane.

IAM G. LINDSAY.

to 100 parts

